PTA 130 Lasers & Light UV

Adverse effects of UV

burning, premature aging of skin, carcinogenesis, eye damage (lens & cornea-cataracts, conjuctivitis, photokeratitis)

effects of PUVA; hyperplasia, hyperpigmentation, cancer risk, can cause nausea & vomiting 1-4 hr after ingesting psoralen

Precautions of UV

photsenitizing meds & dietary supplements → lower the MED increasing risk of burning

photosensitivity → fair skin. light eyes, fair or red hair

recent X-ray therapy → skin is more susceptible to cancer

*no dose should be repeated until effects from previous have disappeared

Contraindications for UV

irradiation of the eyes → wear UV opaque googles, damage of lens, cornea, eyelid damage

skin cancer

pulmonary tuberculosis (antibiotics sensitive to light)

cardiac, kidney, or liver disease (exacerbates)

systemic lupus erythematosus (light sensitivity)

fever

What are you expected to see in UV Wound healing ?

little erythema, tanning associated with it & low carcinogenic effect

Why is UVC used for in chronic wounds?

bactericidal effects, increase epithelial cells turn over rate, accelerates granulation, increase blood flow, increases Vitamin D production, promotes sloughing of necrotic tissue

How do you determine the Minimal Erythemal Dose (MED)

piece of paper is placed in multiple squares with light source positioned at 90 degrees, 24-40 inches aways

exposure occurs in 15 sec increments

Suberythemal Dose

the absence of erythema 24 hrs after UV exposure

Minimal Erythema Dose

the smallest dose that produces erythema that appears 1-8 hrs & fades without trace within 24 hrs

1st Degree Erythema Dose

dose that results in erythema that lasts 1-3 days with clear redness and mild desquamation

dose is approx. 2.5 times the MED & should be used only if the target area is less than 20 % of total body surface

2nd Degree Erythema Dose

a dose that results in intense erythema, edema, peeling, pigmentation, itching

dose is approx. 5 times the MED

3rd Degree Erythema Dose

a dose that results in erythema with severe blistering, peeling, and exudation

dose is approx. 10 times the MED & should be used in areas less than 10 inches

UV Clinical Indications

Acne, chronic ulcer/wound, psoriasis, sinusitis, vitamin D deficiency

UV Therapeutic Effects

bacteriacidal effects, exfoliation, facilitate healing, increased pigmentation, thickening of epidermis, vitamin D production

Effects of Lasers & Lights

increase in ATP production → red (670) & LED (632.8)

increase RNA production for collagen synthesis → red laser light

alters prostaglandin synthesis → laser & LED in red

promote vasodilation → red light & laser

reduces nociceptor activity

results in control of pain & inflammation & promotion of tissue healing

Clinical Indications for Lasers & lights

Tissue healing

Arthritis

Pain management